Kidney stones are a common and painful human health care problem worldwide. Of all stones developed approximately 70% are composed of calcium oxalate. Urinary oxalate is regarded as a driving force for calcium oxalate stone formation, and absorption of dietary oxalate contributes to 10-70% of urinary oxalate. Treatment strategies that significantly reduce the absorption of dietary oxalate and subsequently decrease risk of stone formation are limited if not non-existent. The approach underlying this application is to find an oxalate-degrading enzyme from natural sources (edible fungi) with the ideal properties to be a potential therapeutic, medical food or dietary supplement: stable and active at pH 2.0-5.0, intracellular and/or associated with cell walls, and capable to degrade most available ingested oxalate in the human stomach within the gastric emptying time. This product will ideally be taken with meals and oxalate containing snacks. Such a product is likely to have a wide application within the calcium oxalate stone- forming population. PUBLIC HEALTH RELEVANCE: Kidney stones are a common and painful human health care problem. In Western countries including the United States, approximately 6-12% of the population will develop kidney stones, and of all stones developed approximately 70% are primarily composed of calcium oxalate. Since there is currently no treatment strategy that is effective at degrading oxalate and subsequently reducing kidney stones, Captozyme is proposing to develop an oxalate-degrading enzyme that can effectively act as a dietary intercept and hence reduce the occurrence of calcium oxalate stone development.